This invention relates to machines for automatically placing chips or similar micro-electronic components on printed circuit substrates.
With the advent of the use of chips or similar micro-electronic components on printed circuit boards it has become desirable to develop an assembly apparatus for quickly and reliably placing the component on the board. Further, such a machine must automatically function in response to software controls to obtain the high production speeds desirable to meet the needs of the demand for high numbers of such assembled printed circuit boards.
Because of the small size of the components it has been physically difficult to develop hardware that provides automatic placement of the component on the substrate with any degree of speed, uniformity or reliability. Attempts to accomplish this objective are illustrated in U.S. Pat. Nos. 3,499,203, and 3,453,714, however these devices do not perform every function necessary to completely automate the assembly in the manner of this invention. Machines of this type use a rotary turret device with pickup heads that pick up the component from a source and place the component on a substrate. These devices lack the assembly speed necessary for high production. Other types of placement devices are known as gangbonding machines, U.S. Pat. No. 4,127,432, where a plurality of heads pick up and place the component--but again these machines lack the necessary speed and reliability. Other machines merely use a movable head that picks up and places the component on the substrate. An example of this machine is shown in U.S. Pat. No. 3,611,561. These machines also cannot obtain the desired high speed assembly rates.
With respect to the gangbonding machines, they have theoretical high production rates. However, they are not computer programmable and require manual set-up and changeovers for board design changes and production run changes. Further, they are not reliable in that they require a secondary repair state (often manual) to replace components missing in the machine. They are also dependent on conventional components being present from prior operations.
Thus, it is desirable to provide flexibility in a machine that is computer programmable with on-line repairability.